This invention concerns organopolysiloxane compositions which contain a storage stabilizer with a specific structure. In particular, this invention concerns organopolysiloxane compositions which exhibit excellent storage stability for long periods of time at room temperature and which rapidly cure by a hydrosilylation reaction when heated.
A variety of conventional types of organopolysiloxane compositions have been proposed which are primarily composed of a vinyl group-containing organopolysiloxane, an organohydrogenpolysiloxane and a platinum catalyst to which a stabilizer has been added to improve the storage stability and which are cured when the addition reaction is accelerated by heating (U.S. Pat. Nos. 3,383,356, 3,445,420, and 3,461,185, Japanese Pat. Nos. Sho 51[1976]-28119, Sho 53 [1978]-35983 and Sho 54[1979]-3774). These compositions can be stored for long periods of time as a mixture of all the components and curing occurs only when the compositions are heated.
In particular, addition type-curable organopolysiloxane compositions are known which use a compound possessing a carbon-carbon double or triple bond as the storage stabilizer. Typical examples of the compounds used as stabilizers are tetrachloroethylene (U.S. Pat. No. 3,383,356) and 3-methyl-1-butyne-3-ol (U.S. Pat. No. 3,445,420). These storage stabilizers can effectively inhibit the addition reaction catalytic activity of the platinum or platinum compound and can satisfactorily prolong the pot life of a mixture of all the components in the addition type-curable organopolysiloxane compositions.
However, for the recent diversified demands for performance, the inhibitory activities of these compounds are not satisfactory. Addition type-curable organopolysiloxanes which use these compounds as storage stabilizers slowly undergo an increase in viscosity after being stored for long periods of time. If a large amount of storage stabilizer is used in order to reduce completely the increase in the viscosity, problems occur in that separation occurs due to insufficient compatibility and curing must be carried out at quite a high temperature.